A revised key to the Neotropical cleptoparasitic anthidiine genera (Hymenoptera, Megachilinae) with notes and description of the male of Rhynostelis Moure & Urban.

Rhynostelis Moure & Urban is a monotypic cleptoparasitic neotropical anthidiine genus currently known from two females. Herein, we describe and illustrate for the first time the male and its genitalia and it is confirmed that Rhynostelis parasitizes nests of Eufriesea. An identification key to the genera of cleptoparasitic anthidiine from the Neotropical region is also presented.

Contribution to the knowledge of the Anthidulum Michener and Ctenanthidium Urban (Hymenoptera, Apidae) with new species from Argentina and Peru.

Updated diagnostic generic characters for the neotropical anthidiine genera Anthidulum and Ctenanthidium are presented. Ctenanthidium versicolor sp. nov.

Michanthidium almeidai, a new species from northeastern Brazil (Hymenoptera, Megachilinae).

A new species of Michanthidium Urban (Hymenoptera, Megachilinae)is described and figured from Sergipe and Bahia States, northeastern Brazil. An identification key, illustrations, and a distribution map for the three species of the genus are presented. The male genitalia of Michanthidium almeidaisp.

The identity of the Neotropical stingless bee Frieseomelitta meadewaldoi (Cockerell, 1915) (Hymenoptera, Apidae).

A new study of a surviving syntype of Trigona meadewaldoi Cockerell, 1915, was undertaken and several widely employed names for Neotropical stingless bees recognized as junior synonyms. A lectotype is designated for Trigona meadewaldoi and the following new synonymies established: Tetragona francoi Moure, 1946, and Trigona (Frieseomelitta) freiremaiai Moure, 1963. These nomenclatural matters are here settled and the species thoroughly characterized in advance of a forthcoming phylogenetic consideration of the genus Frieseomelitta von Ihering, 1912.